This invention concerns a device for preparing pipe segments for joining with pipe couplings or fittings. The device mounts tools for performing such functions as impressing a circumferential groove in a surface of a pipe, marking the surface of the pipe, chamfering the end of the pipe and cutting the pipe.
The preparation of pipe segments for connecting to fittings or couplings in a piping network often requires that the pipe be cut, a circumferential groove be formed on a surface of the pipe, the pipe surface be marked at a particular location and that the cut end of the pipe be chamfered to remove burrs or sharp edges resulting from the cutting process. Marking the surface is useful to provide a visual indicator for the proper engagement depth of the pipe in a fitting. Circumferential grooves are often used to provide a locating feature for positioning a sealing means such as an O-ring or gasket, as well as a surface feature for mechanically engaging a coupling to increase the axial pull-out strength of a pipe joint. Cutting is of course necessary to trim pipe stock to a desired length, and chamfering deburrs the cut end and provides a beveled surface which facilitates the entry of the pipe into a fitting.
Forming circumferential grooves in pipes made of malleable materials such as copper, steel and aluminum is accomplished by cold working the metal beyond its yield stress, thereby causing a permanent deformation in the metal. Existing techniques for forming circumferential grooves in metal pipes entail sandwiching the pipe wall between the circumferences of two adjacent rolls or wheels, one wheel being positioned on the inside of the pipe and the other on the outside. One of the wheels has a concave die around its outer circumference into which the circumference of the other wheel can interfit. When the wheels are rotated in opposite directions and sufficient pressure is applied tending to force the wheels together, the pipe wall yieldingly deforms under the pressure of the wheels to form a groove defined by the interaction of the pipe wall with the wheel circumference and the concave die.
The two-wheel method is effective at forming grooves in pipe walls while maintaining the roundness of the pipe because the pipe wall is mutually supported between the wheels and is never subjected to compressive point loads which would tend to collapse the pipe or force it out of round. However, the two wheel method is difficult to implement manually and is of limited value when applied to pipes of relatively small diameter since the inside wheel must be supported on a cantilever which extends into the pipe. Since the cantilever support must fit within the pipe, its physical size and consequently its bending stiffness are limited. For long cantilever lengths or small diameter pipes, the inside wheel may not have a stiff enough mounting to apply sufficient force in reaction to the outside wheel to effect deformation of the pipe wall beyond the yield point.
In addition, existing techniques tend to produce grooves which are concentric with the pipe inside surface. This results in non-uniform groove depths when the pipe wall is of a non-uniform thickness around its circumference. Non-uniform groove depth can degrade the performance of mechanical couplings which interface with the groove to effect the pipe joint.
Pipe cutting is often accomplished by engaging a cutting blade progressively with the pipe while the pipe is supported opposite the blade. As the blade engages the pipe, the pipe and blade are rotated relatively to one another about the longitudinal axis of the pipe until the cut is complete. Chamfering of the cut end may be accomplished by rotating a chamfering wheel or roll around the pipe against the cut end to cold work the metal and bevel the end. Marking of the pipe may be accomplished similarly to grooving the pipe or by rotating an imprinting wheel or a gravure wheel around the circumference.
Pipe preparation, thus, may require cutting, chamfering, grooving and marking. For small diameter pipes as described above, pipe grooving is not readily accomplished by existing means, be they manual or automated. Furthermore, when multiple functions must be performed to prepare a pipe, each function is generally performed with a single dedicated device. Thus, multiple devices are required. This is inefficient when it is necessary to perform multiple functions, as the operator must take the time to engage and disengage the pipe with each device in turn in the processing of the pipe. The inefficiencies are compounded when large numbers of pipe are to be processed. There is clearly a need for a single device which can effectively groove small diameter pipe as well as a device which can perform several or all of the functions required to prepare pipe for joining in a piping network and thus avoid the inefficiencies associated with the use of multiple single function devices.
The invention concerns a device for performing at least one of a plurality of operations on a pipe having a longitudinal axis and an outer circumferential surface. The device according to the invention has a first support with a support surface engageable with the outer circumferential surface of the pipe. A second support is positioned in spaced relation to the first support. One of the supports is movable toward and away from the other.
A tool is mounted on the second support and is positioned facing the first support. The tool is engageable with the outer circumferential surface of the pipe when the pipe is supported on the first support. The tool may be a grooving surface, a marking surface, or a chamfering surface. The plurality of operations which the device may accomplish includes forming a circumferential groove around the pipe with the grooving surface, forming a reference mark circumferentially around the pipe with the marking surface and chamfering the outer surface of the pipe with the chamfering surface. The tool and the pipe are rotatable relatively to one another around the longitudinal axis to effect the operation.
In another embodiment, the device performs a plurality of operations substantially concurrently on a pipe. This embodiment also has a first support with a support surface engageable with the outer circumferential surface of the pipe and a second support positioned in spaced relation to the first support. Again, one of the supports is movable toward and away from the other. A first tool comprising a grooving surface is preferably mounted on the second support and is positioned facing the first support. The grooving surface is engageable with the outer circumferential surface of the pipe when the pipe is supported on the first support. A second tool is also mounted on the second support and is also positioned facing the first support. The second tool is engageable with the outer circumferential surface of the pipe substantially concurrently with the first tool. The second tool may be a marking surface, a radiusing surface, a chamfering surface or a cutting blade, and the plurality of operations performed by the device include forming a circumferential groove around the pipe with the grooving surface, forming a reference mark circumferentially around the pipe with the marking surface, radiusing or chamfering the outer surface of the pipe with the radiusing or chamfering surface, and cutting the pipe with the cutting blade. To effect the operations, the first and the second tools and the pipe are rotatable relatively to one another around the longitudinal axis of the pipe.
In yet another embodiment of the invention, the device has a first support with a support surface engageable with the outer circumferential surface of the pipe and a second support positioned in spaced relation to the first support. One of the supports is again movable toward and away from the other.
The device also has a plurality of tools mounted on the second support and positioned facing the first support. The tools are all engageable substantially concurrently with the outer circumferential surface of the pipe when the pipe is supported on the first support. Preferably, the tools include a grooving surface, a marking surface, a chamfering surface and a cutting blade. The plurality of operations performed concurrently by the device include forming a circumferential groove around the pipe with the grooving surface, forming a reference mark circumferentially around the pipe with the marking surface, chamfering the outer surface of the pipe with the chamfering surface and cutting the pipe with the cutting blade. The tools and the pipe are rotatable relatively to one another around the longitudinal axis of the pipe to effect the plurality of operations.
It is an object of the invention to provide a device for efficiently preparing pipe segments for joining with mechanical fittings.
It is another object of the invention to provide a device which can be used on pipe of relatively small diameter.
It is yet another object of the invention to provide a device which can form grooves in a pipe without the use of a support contacting the inside surface of the pipe.
It is again another object of the invention to provide a device which can form grooves of uniform depth in a pipe relatively to the outside surface of the pipe.
It is still another object of the invention to provide a device which can perform multiple functions substantially concurrently on a pipe.
It is yet another object of the invention to provide a device which is adaptable for manual or automatic operation.
It is another object of the invention to provide a device which has interchangeable components and is adaptable to pipes of different diameters and materials.
These and other objects and advantages of the invention will become apparent from a consideration of the following drawings and detailed description of the preferred embodiments.